Now that disgraced boxer Antonio Margarito has been disposed of, it's time for Manny Pacquiao to look for his next challenge.

Better yet, find any semblance of a challenge, because Margarito, like the many fighters who preceded him, certainly was not.

The one fight the sports world has been clamoring for is a brawl between Manny Pacquiao and Floyd Mayweather Jr. This matchup would easily be one of the most exciting fights of the century, but there have been numerous bumps in the road.

With every fighter—not named Floyd—who Manny notches on his belt, the odds of seeing the two best pound-for-pound fighters duke it out look slimmer by the day.

10. Rift Between Trainer and Promoter

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It appears that a rift between Manny's coach and promoter is starting to heat up.

Bob Arum was recently quoted saying, "Freddie has absolutely no idea what Manny is thinking. Absolutely no idea. Manny relies on Freddie for training. But he does not confide in Freddie as far as his future plans."

Freddy Roach believes that Manny should retire from boxing and he has voiced his opinion over this issue for some time now. His main reason is that there is a lack of qualified opponents for Pacquiao to face, which rings true with a Mayweather fight looking less and less likely to happen. The second reason is that he worries over any potential health issues Manny will face if he continues to fight.

As a businessman cashing in on Manny's immense popularity, Arum cares little about any longterm health issues Pacquiao may face down the road. He looks at Manny and sees dollar signs.

Coach Roach was also not happy with Arum pulling Manny out of camp to go to Las Vegas to aid Senator Harry Reid in his political bid. This came less than a week before the fight, and it was definitely not the sort of distraction that Manny needed.

This sort of disharmony within Manny's camp can only lead to disastrous consequences.

9. Politics Between Top Rank and Golden Boy Promotions

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The two boxing promotion giants—Top Rank and Golden Boy Promotions—have long had bad blood between them.

A slew of marquee matchups never came to fruition because the two companies refused to deal with each other. Even today, the two companies continue to take shots at each other through various media outlets.

The feud reached a boiling point a few years ago when Top Rank's Arum swooped in and stole Pacquiao away from Golden Boy.

While the two companies have since reconciled some of their differences—at least in the public spotlight—Golden Boy is sure to hold a grudge against Top Rank for taking cash cow and current pound-for-pound king, Manny Pacquiao, away from them.

This is sure to keep any potential negotiations a slugfest with neither side willing to commit to the other camp's demands.

4. Pacquiao Is Content with his Accomplishments in the Ring

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During his interview on 60 Minutes, Manny revealed—much to the dismay of boxing fans everywhere—that he was content with everything he has done in the ring and that he has accomplished all his goals in the sport.

Manny's accomplishments in the ring more than speak for themselves. He has nine different titles in a record seven different weight divisions. Pacquiao was also named Fighter of the Decade by the Boxing Writers Association of America.

It appears more and more likely that Pacquiao is inching toward retirement from boxing.

The window for a mega-fight between Manny and Floyd seems to be drawing to a close with every week that passes by.

1. Floyd's Reputation

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Floyd may have an unblemished record, but he's long been criticized for dodging some of the best contenders.

Whether or not he was able to defeat the many challengers who have stepped up to the plate is for another debate, but the fact that he never even attempted to face off against the toughest opponents speaks volumes about him.

Mayweather constantly uses the excuse that Fighter A lost to Fighter B years or months ago, and therefore has no chance against him. But what he does not realize—or is not willing to publicly admit—is that a fighter's style will make the fight.

Floyd is unbelievably gifted and is one of the best defensive fighters in the history of the sport. Fighting Manny would be a clear clash of styles. Manny is a southpaw pummeler and Floyd is a defensive shell. This is one of many reasons why it's such a compelling fight to put together.

Some of Floyd's staunchest defenders will say that he recently took a fight with Mosley—in which Floyd thoroughly defeated Shane—but this was a bout that should have happened years ago when Mosley was still in his prime.

Mayweather continues to spew the nonsense that he's the greatest fighter ever, which is an insult to the many greats who cut their teeth in the ring against the top fighters of their generation.

Floyd hides behind his perfect record, but any rational boxing fan can see that as long as he avoids the strongest challengers, his legacy will never hold up against the likes of Sugar Ray Robinson, Muhammad Ali and countless others.